JPS61285844A - Priority communication control system - Google Patents

Abstract

PURPOSE:To improve the transmission efficiency by distributing the communication right (transmission right) in matching with quantity of communication of each transmitter constituting a network. CONSTITUTION:Data to be sent from a host 3 is stored once in a memory circuit 6 in a node 2, subjected to formatting (packet forming) in a proper way as communication data, sender node address is added as a destination address, a setting value of an address setting circuit 8 is added as a sender address, a token addressed to the own node is received by a reception circuit 11, and then the priority of holding information of a priority information holding section 9 of the own device is higher than the former priority information and the data is sent to a transmission line 1 via a transmission circuit 12 after the transmission right is acquired. Thus, much more communication right transfer is made possible for equipments having higher sending frequency.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application] The present invention relates to a priority communication control system, and particularly to a priority communication control system that controls transfer of communication rights using communication priority designation information in a token.

This specification and drawings describe a priority network system in which a plurality of transmission devices are connected via a communication medium, and only the transmission device that has acquired the communication right using a token, which is a communication rights transfer command, can obtain the transmission right. In the communication control method, the token includes communication priority designation information, and the transmission device includes a receiving means for receiving the communication priority designation information addressed to the transmitting device, and retains the communication priority designation information received by the receiving means. a retaining means for
a comparison means for comparing the information held by the holding means and the communication priority designation information in the token; The present invention discloses a technology that improves transmission efficiency by providing communication right acquisition means that acquires communication rights using tokens, thereby making it possible to efficiently allocate communication rights in accordance with the amount of communication of a transmission device.

[Prior Art] A so-called local area network (LAN) is a network in which a large number of transmission devices (hereinafter referred to as nodes) are connected by sharing a single transmission path, and data communication is performed between these nodes.
is popular. Among the various communication methods in LAN,
The token passing method is particularly advantageous in that it can equally provide communication services to all nodes even when the network is in a high traffic state.

However, in a LAN, one transmission path is usually shared by each node, so if each node is allowed to send calls without management, a situation will occur where two or more nodes will send calls at the same time.
The so-called ``token'' phenomenon occurs, in which data on the transmission path is interfered with.In the token passing method, a communication control code called ``token'', which is a command to transfer communication rights, is circulated within the network system, and this This collision phenomenon is prevented by controlling so that only the node that has acquired (received) the token acquires the right to transmit data.

That is, the note acquires the transmission right only when it receives a token, and if there is a need for transmission, it automatically performs a series of communication processes at this time. Then, when this transmission processing is completed or when transmission processing is not necessary, this token is passed (sent) to the next node.

In this way, each time the transmission of the node that acquired the token is completed, the token is passed to the next node one after another, but this method of passing is designed to circulate all the notes in the network. Each node in the network is given an equal chance of communication, that is, an equal communication service.

FIG. 4 shows the circulating state of nodes in this network system.

Regarding the token circulating method described above, there are two methods, the token bus method and the token ring method, depending on the shape of the transmission path of the network.

In the token bus system, each node is connected to one common transmission path, and tokens circulate in the order of node addresses, for example, according to node addresses specific to each node. On the other hand, in the case of the token ring method, the transmission path connects only adjacent nodes, and when a token is received from one node, the token is sent to the other node. . In other words, tokens are physically passed to neighboring nodes sequentially, but since the network is in a ring shape, they move around the network on purpose. Both methods are the same in that the tokens circulate equally among all the swords in the network.

[Problems to be Solved by the Invention] In this way, each node can receive equal communication services by circulating the token, but for example, if a host computer or file device is connected to a node in the network, In such cases, the frequency of occurrence of these communication requests is extremely high compared to other general terminals.

Even in such cases, with conventional communication methods, the transmission right (token) is circulated only equally among all notes, which delays the transmission of necessary takes and reduces the processing efficiency of the network system as a whole. There was a drawback that it could be stored away.

[Means for Solving the Problem] In order to solve the above problem, multiple transmission devices are connected via a communication medium, and only the transmission device that has acquired communication rights using a token, which is a communication rights transfer command, transmits data. In the priority communication control method of the network system, the transmitting device receives communication priority designation information addressed to the transmitting device, and a holding device holds the communication priority designation information received by the receiving device; a comparison means for comparing the information held by the holding means and the communication priority designation information in the token; and if the comparison result by the comparison means indicates that the priority of the communication priority designation information held by the own device is high, the token is A network system configuration includes a transmission device including a communication right acquisition means for acquiring communication rights.

[Operation J] In a network system configured as described above, a token containing communication priority designation information is received, and only if the communication priority designation information of the own device is higher than this communication priority designation information, the information is acquired by a transmission request as a communication right acquisition. In other cases, even if a token is received, the token is circulated to the next node without acquiring communication rights, making it possible to transfer more communication rights to devices that transmit frequently. .

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of a Mate according to an embodiment of the present invention. In the figure, 1 is a LAN network transmission path, 2 is a node which is a transmission control device, and 3 is a block diagram of various computer equipment and office work connected to node 2. It is a device.

The node 2 includes a transmitting circuit 11/receiving circuit 12 that performs data communication with the transmission path 1, a token discriminating circuit 4 that determines whether or not the data received by the receiving circuit 12 is a token, and a token discriminating circuit 4 that performs overall control of the mate and controls the transmission data. A control unit (hereinafter referred to as CPU) 5 that performs processing, decoding and disassembly of received data, timing control v4 of communication operations, etc., a memory circuit 6 that stores transmitted and received data, etc., and an interface circuit 7 with the host 3. An address setting section 8 and a priority information holding section 9 are configured of a switch and the like to set a unique address number for a note.A comparison is made between the priority information in the token and the priority information held in the priority information holding section 9. It consists of a comparison circuit 10 and a destination address determination circuit 13.The address value set in the address setting section 8 is read by the CPU 5 and used as the destination address and source address during transmission and reception.

The data to be transmitted from the host 3 is temporarily stored in the memory circuit 6 in the node 2, and is appropriately formatted (packetized) as communication data, and the destination node address is set as the destination address value and the address setting circuit 8 After adding the set value of as the source address, the receiving circuit 11 receives the token addressed to the node, and the priority information of the information held in the priority information holding unit 9 of the own device is higher than the priority information of the token, Only when the transmission right is acquired can the signal be sent to the transmission path 1 via the transmission circuit 12.

On the other hand, the other node receives the communication data on the transmission path l, checks the destination address value in the received data in the destination address discrimination circuit 13, and checks the setting value of the address setting circuit 8 in the own node, that is, the value addressed to the own node. If it is determined that it is data, it is notified to the CPU 5, this data is taken into its own node, and after some disassembly and editing processing is performed by the CPU 5, it is delivered to the connected host 3.

In addition, in the token passing method, all the data flowing on the transmission path l is not only the communication data between the hosts 3, but also the communication data between the CPU in each node such as a token and the CPU of the destination node. It also includes so-called communication control data.

Based on the above hardware configuration and the above-mentioned principle of token passing, each node in the network receives and passes tokens to downstream nodes one after another, thereby performing communication using a single transmission path. That's why.

The structure of a transmission frame circulating in the network system of this embodiment is shown in FIGS. 2(A) and CB).

In the figure, 200 is a token frame, 201 is a source address (hereinafter referred to as SA), 202 is a destination address (hereinafter referred to as DA), 203 is a token code representing the token frame, 204 is a priority specification code, and 205 is a A transmission code 206 representing a data frame is transmission information.

The data transmission control of this embodiment will be explained below with reference to the flowchart of FIG.

First, in step St, it is monitored whether or not a transmission frame is received from the transmission path l. When a transmission frame is received, the process proceeds to step S2, and the destination address determination circuit 13 sets the DA 202 and address setting circuit 8 in the received frame. and the own node address value. If the two values do not match, that is, if the transmission frame is not addressed to the own node, the process proceeds to step S3, where the received data frame is directly sent from the transmission circuit 12 to the transmission path 1, and the process returns to step S1.

If the transmission frame is addressed to the own node, the process proceeds to step S4, where the token discrimination circuit 4 is activated and checks the transmission code area (203.degree. 205) in the received transmission frame to determine whether this is the token code 203 or not. In the case of reception of a token frame, the process advances to step S5, and the comparison circuit lO
is activated, and the priority designation code 204 is compared with the data held in the priority information holding unit 9. As a result, if the priority of the second node is higher, the process proceeds to step S7, where the transmission right is acquired by the received token, and in step S8, whether there is data to be transmitted from the host 3 or the second node, that is, there is a transmission request. If there is a transmission request, a unique node address of the destination node is sent to the DA 202 in step S9.
The own node address set by the address setting circuit 8 is set to 5A201, and then the transmission code 2
05, the transmission information 206 is set, a data transmission frame 250 is generated, and in step 310, this data transmission frame 250 is transmitted to the transmission source node according to a predetermined transmission control procedure. When the data transmission process is completed, in step 311, the next mate (downstream node) address to which the token should be passed is set in the DA 202, the own node address is set in 5A 201, the token code is set in 203, and the priority designation code is set in the DA 202. In 204, set the priority specification sent to the eye node as is,
After generating this token frame 200 and sending it to the downstream node and transferring the transmission right, the process returns to step 31.

On the other hand, the token frame 200 received in step S6
If the priority specification code 204 of the node is higher than the priority held in the priority information holding unit 9 of the own node, the node is not allowed to acquire the transmission right, and the process proceeds to step 311, where it immediately generates a token frame. Send the token to the downstream node. Also, if there is no transmission request in step S8, the process proceeds to step Sll in the same manner, and the token is sent to the downstream node.

If the token is not received in step S4, the process proceeds to step 320, in which the data transmission frame 250 addressed to the own device is received within the own node according to a predetermined transmission control procedure, and the transmission information received in step 321 is transmitted to the host 3. It is checked whether the information should be sent to the host 3, and if it is the information that should be sent to the host 3, the process proceeds to step S22, where this information is slightly disassembled and edited, and then sent to the host 3 connected to this node, and the process proceeds to step S1. and prepare for the next data transmission.

If the data is not to be transmitted to the host 3, that is, if it is information for changing the content held in the priority information holding unit 9, which will be described later, the process advances to step S30, where processing corresponding to each received data is performed, and then step S1 Return to

Therefore, the priority specification information added to the token information is
In this case, it acts as a filter to select nodes that receive communication services.

The circulating state of the token in the above explanation is the fourth
They circulate in the order of cgJ, and 100 to 170 correspond to node 2 shown in FIG. 1, respectively. This node A 100 is a node that can be called a master node of the network system, and sets the priority designation code 204 in the token frame 200, which is dynamically set in relation to the token circulation period.

The reproduction setting process of the priority designation code 204 of the node A 100 will be explained with reference to the token circuit diagram of FIG.

In this embodiment, the retention level of the priority information retention unit 9 of each node is set to the level shown below.

In the node A 100, the priority specification code 204 is set to "3" in the first round of the token, to 2 in the second round, to "1" in the third round, and again in the fourth round. 3'' and change the above priority designation periodically according to the token cycle period.

Figure 5 (A) shows the nodes that acquire the transmission right when the level is "3", Figure 5 (B) shows the nodes that acquire the transmission right when the level is "2", and the nodes that acquire the transmission right when the level is "2" are shown in Figure 5 (B). In FIG. 5C, the nodes that acquire the transmission right at this time are indicated by diagonal lines.

As shown in the figure, the higher the number of levels, the higher the priority is given. Like this, level 3 nodes (e.g. node 0120)
can obtain transmission rights three times more frequently than a level 1 node (e.g. node F 150), and a level 2
A node of 1 can acquire the transmission right twice as often as a node of 7 at level l.

If the host connected to the node is connected to a device with a high communication load, such as a host computer or a file device, by setting the priority of the node to a high level, the communication It is possible to proceed with the processing significantly faster.

The priority information holding unit 9 of the node described above is constituted by a digital switch, and can be set to any level from level 1 to level 3 depending on the model of the connected host 3.

However, this priority information holding unit 9 does not necessarily set a fixed priority level by hardware, but can also dynamically set the priority level to an optimal value by software. For example, when starting up the network, one communication Once each node is started with the priority setting set to a specific value (default value), and when communication becomes possible, the specific node (for example, node C120) sends priority setting data as communication data to each node. and each node uses this sent priority setting data,
For example, it is stored in the priority information holding unit 9 configured with RAM. An example of this priority setting data transmission frame 300 is shown in FIG.

In the figure, 207 is a priority level transmission code indicating that the transmission frame is a priority information transmission frame, and 208 is priority information.

When this transmission frame is received, the priority information 208 sent as the process of step S30 in FIG.
It may be stored in the priority information holding unit 9 through the processing of the PU 5.

The specific node may be connected to a device having a non-volatile memory such as a file device as the host 3, and priority information for all nodes in the network may be registered in advance in this file device.

Figure 7 (A) shows an example of network priority setting at startup, and an example when the sending (setting) of the priority information 208 to each node has been completed and the priority resetting has been completed. Figure 7 CB) is shown.

The set priority is shown within the frame of each node.
X is a default value which is a specific value. Figure 7 (A)
Based on the state shown in , optimal priority information is set for each node by taking into consideration the network traffic volume, etc.
The priority information may be set as shown in Figure CB). For example, if a host 3 connected to a file device, No. 1" Cl2O, transmits the transmission frame 300 shown in FIG.
This is done by sending x1 to x as the priority level.
6 is set for each node.

Furthermore, in the above explanation, the priority specification code 204 in the token frame 2゛OO that circulates within the network has been explained as an example in which only a specific node within the network can change and set it. This can be done not only by all nodes, but also by all nodes. In other words, from the time each node powers on and starts up, each node receives the next 7 nodes every cycle (or every multiple cycles) in which the token circulates to its own node. The priority specification code 204 in the token frame 200 to be passed to is changed. In this case, as in the previous embodiment, it is not possible to perform unified control such that the entire network provides communication services for mates with the same priority level or higher, but at least from a node-to-node perspective, as shown in FIG. As shown in (A) to (C), the node with a higher priority setting can acquire more transmission rights and have more communication opportunities.

All seven members have the right to change this priority specification code 204.
- The code may be uniformly available, or it may be controlled so that only mates with a specific priority level can perform it.
FIG. 8 is a state diagram showing an example in which node A100 hands over the acquired token (i.e., transmission right) to a downstream node, and O
The node indicated by diagonal lines is the node that acquires the transmission right, and the node indicated by O is the node that cannot acquire the transmission right even if it receives the token frame 200 and passes it to the next node as is.

In addition, the priority level in the diagram is Node D>Node C>Node B.

The node A 100 updates the priority designation code 20 in the token frame 200 every time the token frame 200 circulates.
4 shows an example in which the signal 4 is periodically changed from a high level to a low level.

The advantage of this method is that it is completely decentralized, unlike the previous embodiment, which relied only on a specific node to change the priority specification information in the token. The point is that it can be made into a strong network.

Furthermore, in this embodiment, an example was explained in which the priority designation code 204 in the token frame 200 determines the priority, but this priority designation code is not defined in a separate area but is included in the token code 203. Then, a separate token code is assigned to each priority level as the token code 203, and the node that receives this token frame 200 decodes (deciphers) this token code and extracts the priority level. This reduces the amount of data transmitted over the network, making it possible to create a network system with high data transmission efficiency. In this way, it is sufficient that the entire token frame 200 includes information indicating some kind of priority designation.

Furthermore, although the above explanation has been made based on a token ring type network, the present invention is not limited to this, and transmission control may be performed using exactly the same processing even in a token bus type network configuration.

Effects of the Invention 1 As explained above, according to the present invention, efficient communication rights (
transmission rights) can be distributed.

A preferential communication control method for a network system with high transmission efficiency can be provided.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of nodes configuring a network system according to an embodiment of the present invention. FIGS. 2(A) and 2(B) are transmission frame configuration diagrams used in this embodiment. Figure 883 is a data transmission control flowchart in the 7th mode of this embodiment, Figure 4 is a token circulation state diagram in the network, and Figures 5 (A) to (C) are transmission right acquisition state diagrams of each node in this embodiment. . FIG. 6 is a configuration diagram of a priority level transmission frame in another embodiment of the present invention, and FIGS. 7(A) and (B) are diagrams of priority information setting states at each node in another embodiment of the present invention. FIG. 8 is a priority designation state transition diagram at node A according to still another embodiment of the present invention. In the figure, l...transmission path, 2,100-170...node, 3... host, 4... token discrimination circuit, 5...
...CPU, 6...Memory circuit, 8...Address setting circuit, 9...Priority information holding unit, IO...Comparison circuit, 11...Receiving circuit, 12...Transmitting circuit, 13・
... Destination address discrimination circuit, 203 ... Token code, 204 ... Priority designation code, 205 ... Transmission code, 207 ... Priority level transmission code, 208.
...Priority information. Only 5 figures (A') 35 prisoners (B) +60 15Q 140 Figure 6 Figure 7 (A) Figure 7 (''8)

Claims (2)

[Claims] (1) In a priority communication control method for a network system in which multiple transmission devices are connected via a communication medium and only the transmission device that has acquired the communication right by a token that is a communication right transfer command obtains the transmission right, the token is a receiving means that includes communication priority designation information and receives the communication priority designation information addressed to the transmission device itself; a holding device that holds the communication priority designation information received by the receiving device; a comparison means for comparing the held information with the communication priority designation information in the token, and if the comparison result of the comparison by the comparison means is that the priority of the communication priority designation information held in the own device is high, the communication right is granted by the token; 1. A priority communication control method comprising: means for acquiring communication rights. (2) The priority communication control method according to claim 1, wherein the communication priority designation information is sent from a specific node within the network system.